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Low voltage white LEDs.

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  Low voltage white LEDs. "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-11 20:20 +0100
    Re: Low voltage white LEDs. Jon Elson <elson@pico-systems.com> - 2017-05-19 21:18 -0500
      Re: Low voltage white LEDs. "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-20 20:48 +0100
        Re: Low voltage white LEDs. Jon Elson <elson@pico-systems.com> - 2017-05-20 18:58 -0500
          Re: Low voltage white LEDs. "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-21 22:25 +0100

#6084 — Low voltage white LEDs.

First bicycle headlamps and now an under shelf light.

I'm starting to find white LEDs that run from 2x AAA cells - can't find any 
boost circuit at all.

Anyone got a link to a data sheet that explains this?

Thanks. 

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#6085

Ian Field wrote:

> First bicycle headlamps and now an under shelf light.
> 
> I'm starting to find white LEDs that run from 2x AAA cells - can't find
> any boost circuit at all.
> 
> Anyone got a link to a data sheet that explains this?
> 
> Thanks.
The latest white LEDs seem to drop about 2.6 V or so at lower current.  So, 
just get some big LEDs and run them at reduced current, and they should run 
off 3 V from Alkaline cells.  Likely they would be real dim and fade quickly 
on NiMh cells.

Jon

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#6086

"Jon Elson" <elson@pico-systems.com> wrote in message 
news:FqKdnaaPjrkSOoLEnZ2dnUU7-aOdnZ2d@giganews.com...
> Ian Field wrote:
>
>> First bicycle headlamps and now an under shelf light.
>>
>> I'm starting to find white LEDs that run from 2x AAA cells - can't find
>> any boost circuit at all.
>>
>> Anyone got a link to a data sheet that explains this?
>>
>> Thanks.
> The latest white LEDs seem to drop about 2.6 V or so at lower current. 
> So,
> just get some big LEDs and run them at reduced current, and they should 
> run
> off 3 V from Alkaline cells.  Likely they would be real dim and fade 
> quickly
> on NiMh cells.

Trying that would probably tell me something I didn't know.

There's a shelf light laying about on my desk - so far I just couldn't be 
bothered charging a couple of AAA cells to try. 

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#6087

Ian Field wrote:


> Trying that would probably tell me something I didn't know.
> 
> There's a shelf light laying about on my desk - so far I just couldn't be
> bothered charging a couple of AAA cells to try.
I built a few fluorescent retrofits with strings of 20 1 Watt LEDs, so I had 
to know a bit about the LED characteristics to do it right.

Jon

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#6088

"Jon Elson" <elson@pico-systems.com> wrote in message 
news:v5OdnQQrouOIRb3EnZ2dnUU7-X2dnZ2d@giganews.com...
> Ian Field wrote:
>
>
>> Trying that would probably tell me something I didn't know.
>>
>> There's a shelf light laying about on my desk - so far I just couldn't be
>> bothered charging a couple of AAA cells to try.
> I built a few fluorescent retrofits with strings of 20 1 Watt LEDs, so I 
> had
> to know a bit about the LED characteristics to do it right.

The ones I have just turned up on the market - I was curious how they got 
away with running them off 2 cells and no boost circuit. 

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